This is an open-label, phase I study of a recombinant fusion protein (mutated SEA superantigen linked to Fab fragment recognizing a tumor-associated glycoprotein 5T4) PNU-214936 in patients with advanced non-small cell lung cancer. Primary side effects of PNU214936 observed, included transitory hypertensive episodes, fever/chills and fatigue (most frequent side effects). The primary objective of this study is to determine the MTD of PNU-214936 as a function of pretreatment anti-SEA antibody levels by giving infusions for 4 consecutive days in patients with advanced NSCLC. Secondary objectives includes safety profile, tumor response, immunological response and pharmacokinetic parameters.